TL;DR - ES2020: Nullish Coalescing

![](/media/2020/nullish-coalescing/nullish-coalescing-dark.png)

The [nullish coalescing proposal](https://github.com/tc39/proposal-nullish-coalescing/) (`??`) adds a new short-circuiting operator meant to handle default values.

The nullish coalescing operator (`??`) acts very similar to the `||` operator, except that we don’t use _"truthy"_ when evaluating the operator. Instead we use the definition of _"nullish"_, meaning "is the value strictly equal to null or undefined". So imagine the expression `lhs ?? rhs`: if `lhs` is not nullish, it evaluates to `lhs`. Otherwise, it evaluates to rhs.

```js
false ?? true // => false
0 ?? 1 // => 0
'' ?? 'default' // => ''

null ?? [] // => []
undefined ?? [] // => []
```

# References

- https://github.com/tc39/proposal-nullish-coalescing/
- https://v8.dev/features/nullish-coalescing